Use Proactive Headsup user's email for first and last name fields in Salesforce rather than producing an error and doing nothing.
Salesforce Lead records require Last Name, Company and Lead Status.
I don't like a bazillion fields on Proactive Headsup so I just ask for First Name and Email.
But then I get an error: Couldn't be synced as a Salesforce Lead. Required fields are missing: [LastName].
Proactive Headsup doesn't ask for Lead Status or Company but you're smart enough to automatically populate these required fields.
So why not do the same thing for Last Name (and First Name if that is not asked)?
If no last name is provided, just use the first name in both first and last name fields.
If neither first nor last names are provided, use the email address in these fields.
Or just use "[not provided]" in these fields as you do for company name.
That way the lead would at least get into Salesforce. If it's in Salesforce it can be updated with this info later. If it's not in Salesforce then my marketing automation is completely broken.
Throwing an error message and not syncing the lead with Salesforce is a terrible solution to an easy problem.